package org.dstadler.jgit.api;

/*
   Copyright 2013, 2014 Dominik Stadler

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

     http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
 */

import org.dstadler.jgit.helper.CookbookHelper;
import org.eclipse.jgit.lib.ObjectLoader;
import org.eclipse.jgit.lib.Ref;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.revwalk.RevCommit;
import org.eclipse.jgit.revwalk.RevTree;
import org.eclipse.jgit.revwalk.RevWalk;

import java.io.IOException;

/**
 * Simple snippet which shows how to retrieve a Ref for some reference string.
 */
public class ReadBlobContents {

    public static void main(String[] args) throws IOException {
        try (Repository repository = CookbookHelper.openJGitCookbookRepository()) {
            // the Ref holds an ObjectId for any type of object (tree, commit, blob, tree)
            Ref head = repository.exactRef("refs/heads/master");
            System.out.println("Ref of refs/heads/master: " + head);

            System.out.println("\nPrint contents of head of master branch, i.e. the latest commit information");
            ObjectLoader loader = repository.open(head.getObjectId());
            loader.copyTo(System.out);

            System.out.println("\nPrint contents of tree of head of master branch, i.e. the latest binary tree information");

            // a commit points to a tree
            try (RevWalk walk = new RevWalk(repository)) {
                RevCommit commit = walk.parseCommit(head.getObjectId());
                RevTree tree = walk.parseTree(commit.getTree().getId());
                System.out.println("Found Tree: " + tree);
                loader = repository.open(tree.getId());
                loader.copyTo(System.out);

                walk.dispose();
            }
        }
    }
}
